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Radius 25W to 2W mod?
Posted: Mon Feb 28, 2011 4:18 pm
by ve1gln
Anyone know how I could mod a 25W radio to make it a 2W one?
I don't want to turn down the TX power, as I think it makes it noisy. so 2W at full power should do what I need.
Thanks in advance.
Glen
VE9GLN
Re: Radius 25W to 2W mod?
Posted: Mon Feb 28, 2011 7:16 pm
by Al
You didn't say which Radius, but the current ones have a programmable high and low power setting. If you have a 1-25W, just program both high and low for whatever you want within the range of 1 and 25 W.
Re: Radius 25W to 2W mod?
Posted: Tue Mar 01, 2011 4:26 am
by ve1gln
It's a M100 or M200/214 however you wanna look at it.
turning down the power in these causes it to emit spurious emissions. I would like to get it to 2W PA. /\/\ sold a 2W/25W/45W version. I am thinking there must be an easy way to
change the 25W to a 2W version... Maybe just remove the final and jump the connection?
Glen
VE9GLN
Re: Radius 25W to 2W mod?
Posted: Tue Mar 01, 2011 4:59 am
by Al
I don't believe that you would get 2 W just taking output from the RF board, more like 600 mw. And you would lose any power leveling that the firmware/variable gain IPA provides. If you're just using the transmitter portion, it would make more sense to set it at 10 W and use a power attenuator to get to 2 W.
M built an industrial version that's adjustable to 1 W, max 10 W. One of those would do what you want nicely.
Re: Radius 25W to 2W mod?
Posted: Tue Mar 01, 2011 5:15 am
by ve1gln
Al wrote:I don't believe that you would get 2 W just taking output from the RF board, more like 600 mw. And you would lose any power leveling that the firmware/variable gain IPA provides. If you're just using the transmitter portion, it would make more sense to set it at 10 W and use a power attenuator to get to 2 W.
M built an industrial version that's adjustable to 1 W, max 10 W. One of those would do what you want nicely.
Hmmm...There is about 200mW coming from the RF board feeding the PA to the first stage, which I thought was the 2W one, then the final stage which was 25W. I remember seeing a schematic of the PA and the difference between the @%w and 2W was that the final rf amp was not there, and it was jumpered... I just can't find that document any more, so I have no "certain" indication of how to accomplish this.
Thanks
Glen
Re: Radius 25W to 2W mod?
Posted: Tue Mar 01, 2011 5:40 am
by jhooten
I went through this a few years ago. First is there a regulatory reason you want to limit it to 2W or is it technical? If it is regulatory and you modify the PA you may not be in compliance. The mods void the certification according to the FCC engineer I was talking to.
Cutting to the chase, the quickest, cheapest, easiest, and best all around solution to the problem was to trade the radio with someone who had a 2W and wanted a higher power unit.
Re: Radius 25W to 2W mod?
Posted: Tue Mar 01, 2011 5:46 am
by ve1gln
jhooten wrote:I went through this a few years ago. First is there a regulatory reason you want to limit it to 2W or is it technical? If it is regulatory and you modify the PA you may not be in compliance. The mods void the certification according to the FCC engineer I was talking to.
Cutting to the chase, the quickest, cheapest, easiest, and best all around solution to the problem was to trade the radio with someone who had a 2W and wanted a higher power unit.
Yeah, I'm thinking it might be easier to see if someone can trade me a 2W PA for my 25W PA
Thanks for the help.
Glen